If there are enough creatures with evolve, this might just be one of the mechanics that is easiest to build around. As dontrike said, if there's like a 1/1 with evolve, this could easily turn into a very swift aggro or tempo deck. Let's wait and see. Also, it's easy to imagine shenanigans with a cheap evolver, an ETB creature with higher p or t and angel of restoration.

Gatecrash previews have unofficially officially begun. (They don't start until next week, but Wizards is starting early for Holidays and such.)

This may not be constructed worthy, but draft and sealed this is quite the power house. I know I don't mind getting a bonus for playing bigger creatures only for my reward to be bigger creatures to draw more.

Boros today. The guild mechanic is pretty cool and everything with it is Ordric. Helix Angel is pretty amazing and I bet will find a home somewhere. The fact that Lightning Mauler exists (and Fervor) means that you can easily make her have haste and killing something and possibly surviving the next turn.

Doesn't seem very constructed playable, although it depends on the removal in GTC. Right now, there's not much that kills a 4/4 multicolored creature, so if that doesn't change, we might see this one pop up in standard.

I really like extort, though. Fun and flavorful mechanic. You can only use it once, but if you have multiple extort cards, it could quickly get out of hand. I would LOVE to see a creature like this: